Safety appliance



Sept. 17, 1946.

SAFETY APPLIANCE Filed May 22, 1943 GEORGE w. McKlNSTRY INVENTOR 'ITORNEYS G. w. MCKINSTRY 2, 7,

Patented Sept. 17, 1946 YUNITQED STATES orn ce -to 'Bausch & Lomb Opticz'ilflflompany, Roch.- ester, N. Y., a corporation of'New'York Application May 22, 1943, Serial N0.Y488,0V75

' .5 Claims. (o1; 7. 15615) This invention relates ,to a safety appliance and :more' particularly: to a locking device for uards used on punch presses, stamp achines, iandwthe like.

:Heretofore, it has been -,customary to provide a uardfor stamping machines which utilize-a l ver arran ement ,for permitting themachineto be operated when a shield afiixedthereto has been positioned in .front of the orperatorto protect the person. of theoperator frominjury caused {by accidentaliorcibie dislodgmentof th wo kpi e- :Asthe. shield was p siti ned in, its pr e t ve. p ane y depression of. a handle afl x d t alever controllin the opera ion f the. a m h n the lever arran ement would automatically opera e the ma hin permittin one of the dies to forcibly impact'theworkpiece onthepther die. Thus, the .function of the uard was primarily usedlas a protection for safeguarding the operator from theiorcible ejection of the workpiece on'the person of-theop rator- ;In the actual'us ofthezguard, the operator positioned .and removed :the workpiece on the stati na y-die with ne hand wh le the th r hand depressedjthe handleto bring the shield in front f he-operat r, an toactuate h mach n Due tothc failure to coincide the. movements. of the hands, in performingthis,operation, the hand manipulating the workpiece was frequently inin dhy: the movable die. becaus the p rator did notremove-the hand in theinterchange of workp e w t the st tionarvdie in unis w th t e other hand actuating the machine-operating handle or by the negligence inthe operation of the machin .Thusithe guard failedflto protect the hands of t .eoneraton-and it is an object of the present invention toprovide mechanical means employing {the use ofw'both of the 'hands for securing operation of the machine, and to thereby safeguard the hands, ofthe operator from injury resulting from interference with the shaping elements of the machine. This desirable result is achieved by employment of a locking device that retains the guard. in an inoperative position and which must be, released andheld by one hand of theoperator while theotherhand depresses the handle on the guard "to secure operation of the machine. In this manner, "both hands of the operator are used .to actuate members instrumental for operanon ofthe machine, which precludes injury to the hands by. the negligence of the operator.

,The present invention is particularly adapted t -saieguard the hands-of the machine operator in'modern production methods. It is of parathewo kn cccsand t e a ion o t e machin .WO lQJ this ha act rt nd t n ender care- .iessness and ne li nc in .the ct ns h onratordueto the spe d d ma d d. and also-pr motesiati ue of t e mental d physical iaculties, resulting infailureto coord nate thesezfacule ties to secure optimum safety in the use of the a d e. a et a p ance of theprescnt inventionpermits the operator to secure the desirable benefits of the pieceworksystem, while guar .anteeing the safety of the hands of the operator.

Othernovel objects and advantages ofthepresent invention will appear from. the following. description taken in connection-M1311 the acompanying drawing in which: a I

.Fig. 1 is a-frontelevation of, my device attached to a stamping machine.

Fig. 2 is a perspectiveview-of my deviceapplied to a guard of a stamping machine. Fig. 3 is a sideel-evation of my device.

Fig. 4 is a. perspective view. of a fragmentary portion of the guard andsafety appliance.

The device of the present invention, for the purpose of illustration, has} been shown attached to a stamping machine. 1 V V The stamping --machine, in the present instance, is shown as ,a conventional punch press having th usual 'frame'members, generally indicated by the numerals .IB and I I. Between these members there is mounted the operating mechanism comprising acrank shaft l2 to which a plunger [3 is connected for,reciprocation thereon. The plunger l3 has an attached coupling member for receiving .a removable die 14. The die is movableby the plunger to contact a workpiecesupportedon a stationary die mounted in. a bedplate l5 on a shelf I 6 integral with the press. Located at onesideof the press is a lever I! for; controlling the motive power operating the press. When the lever I! is pulled downwardly. the lever will 1161'- mit. the motivatingiorce :to actuate the crank shaft 12 for reciprocating th plunger 113. The

plunger l3 will force the die l4 onto the workpiece held by th stationary die, forming the workpiece'into a desired shape.

In the use of the punch press, itiisla common ractice to provide a guard to be positioned between the die *bedplate. and the operator ,to protect the operator from the workpiece should it'be tecting position. When piece on the stationary lured by the descending be adjusted to bring the end face incorrectly struck by the movable die and from fragments broken off from the workpiece when the workpiece is struck by the die. Such guards, generally when lowered to their protecting position, will actuate mechanism to operate the press. The guard, as herein shown, is pivotally mounted at one side of the bedplate of the press and comprises a lever l8 and a transparent shield IS. The lever '18 isfixed in a collar pivotally secured toa yoke 2| on the power controlling lever l1 and is pivotally attached to the shelf press by means of a pin 24 passing through openings in a coupling member 22, a collar 23-, and the lever l8. The shield l9 comprises a plate 26 of toughened transparent material fixedly secured in a frame 21. The frame 21 has its ends formed in the shape of loops to encircle the lever l8 and is securely fastened thereto. A handle 28 is attached to the lever |8 for manual manipulation of the lever. A spring 229 is fastened to the frame of the press and the yoke 2| of the lever H to resist in pulling the lever l1 and the attached lever l3 downwardly to their operative positions, and-to normally hold the shield out of its prothe handle 23 is forcibly depressed by the operator, the guard will move downwardly to a position intermediate the bedplate and the operator, and actuate the lever H to cause the operation of the press. It will be clear that the guard when moved to its press operating position will prevent injury to the operator'by accidental discharge of the workpiece or fragments thereof when the workpiece is struck by the die.

Many operators to increase their production, while operating the guard with one hand, used their other hand to position the unshaped workdie and sometimes to remove the shaped workpiece therefrom after operation of the press. In so doing, the hand of the operator manipulating the workpiece, due to fatigue or activity engendering carelessness or negligence, may fail to coordinate itself with the hand actuating the guard and is frequently indie.

The safety appliance of the present invention is particularly adapted to prevent injury to the free hand of the operator by incorporating with the guard other mechanism which, spaced from the handle 28, requires actuation by the free hand beforethe guard can be lowered. This mechanism, in the broader aspects of the present invention; may comprise any means which forces the operator to use his free hand to actuate the same just prior to the actuation of the guard by his other hand. In the now preferred embodiment of the present invention, this means comprises a post 3| pivotally connected by a pin 33 to a bracket 34 mounted on the shelf IS. A bar 32, carried by the post 3|, extends upwardly thereof and terminates in a flared portion presenting a relatively long end face. The bar 32 is adjustably mounted to the post 3| by means of bolts 38 passed'through a slot formed in the post and threaded intotapped sockets in the bar 32. As

the bar is movably mounted to the post, it may thereof to a position underlying the freeend of the lever l8. It will be seen that with the bar 32 in a position wherein the end face thereof underlies the end of the lever, it will be impossible for an operator to lower the guard carried by the lever. As the end face of the bar 32 is relatively wide, it will be effective to prevent movement of the lever even though thelever is notperfectly aligned with the '6 Of the.

' the lever to ride over 2 ing the handle portion of the trip turn the end face bar such as might occur through wear of the coupling parts.

To permit the guard to be lowered in the operation of the press, a trip arm 35, fixed to the post 3|, is formed with a handle portion spaced from the handle 28 of the lever and which must be grasped by one hand of the operator to pivotally move the bar 32 out of the position shown in Fig. 2 to one wherein the end face thereof no longer interferes with the actuation of the lever 18.

To relieve the operator from manually actuatarm 35 to reof the bar 32 to a position unl8, means are provided in the present invention for automatically performing this actuation for the operator. Although various means may be used to secure this desirable result, in the now preferred embodiment of the invention, this means comprises a spring 36, one end of which is fixed to the bracket 34 while the opposite end is connected to the post 3|. The spring 36 pivotally moves the post 3| and the bar 32 rearwardly to a position wherein the end face of the bar 32 again lies beneath the end of the lever IS. A stop pin 34, fixed to the bracket34 limits the return movement of the post 3| and defines the position of the same face of the bar 32 is disposed beneath the free end of the lever l8. 1

It will be seen now that depression of the trip an'n 35 by one hand of the operator pivotally moves the end face of the bar 32 from its normal position underlying the lever l8 so that the same may be lowered by depression of the handle 28 by the other hand of the operator to actuate the press. Due to the action of the spring 36, the trip arm 35 must be pushed downwardly and retained in its lowermost position by the one hand of the operator until the guard is lowered. Of necessity, the operator must employ both hands to secure operation of the press, thus insuring freedom from injury to the hands, by eliminating any possibility of the the descending die and the stationary die.

To insure that the lever I8 will return to its normal position over the free end of the bar 32 and without restraint that might-otherwise be provided by the under surface of the flared portion of the bar 32, the bar 32 is formed along its rear edge with a cam surface 39 to be engaged by the end of the lever l8 upon its return movement. Thecamming action brought about by the sliding engagement of the lever |8 along the rear edge of the bar 32 forces the same forward against the action of the spring 36 and permits the nose of the cam and assume its normal position as shown in Fig. 2.

From the foregoing, it will be apparent that I am able to attain the objects of my invention and provide a new and improved safety appli ance which is efficient and trustworthy in operation. Various modifications of structure can-be made without departing from the spirit of my invention or the scope of the appended claims.

I claim: r 1. In a machine of the type described having a bedplate for holding a workpiece to be acted upon by a die, the combination of means for moving said die into work engaging position; guard means adapted to be actuated by one hand of an operator and movable to a position intermediate said bedplate and the operator, .said guard means actuating said moving means as the same is moved to said intermediate position; means for locking said guard means against derlying the lever in which the end 7 hands being inserted between movement; and means spaced from said guard means and requiring the other hand of the operator to actuate the same to release said looking means.

2. In a machine of the type described having a bedplate for holding a workpiece to be acted upon by a die, the combination of means for moving said die into work engaging position; guard means mounted at one side of said bedplate and adapted to be actuated by one hand of an operator for movement to a position intermediate said bedplate and the operator, said guard means actuating said moving means as the same is moved to said intermediate position; means for locking said guard means against movement;

said guard means; and means mounted on the other side of said bedplate and requiring the other hand of the operator to actuate the same to release said locking means.

3. In a machine of the type described having a bedplate for holding a workpiece to be acted upon by a die; the combination of means for moving said die into Work engaging position; uard means mounted at one side of said bedplate and adapted to be actuated by one hand of an operator for movement to a position intermediate said bedplate and the operator, said guard means actuating said moving means as the same is moved to said intermediate position; means for normally holding said guard means out of said intermediate position; means mounted on the other side of said bedplate for locking requiring the use of on hand of the operator in order to permit actuation of the guard means by the other hand of the operator to operate said machine.

4. In a machine of the type described having a bedplate for holding a workpiece to be acted guard means actuating said moving means as the same is moved to said intermediate position; means for normally holding said guard means out of said intermediate position; means mounted on the other side of said bedplate for locking said guard means against movement; means carried by said locking means and requiring the other hand of the operator to actuate the same to release said locking means; means for returning said locking means to 'a normal operative position upon release of the actuating means of said locking means, the said holding means moving said guard means out of to said moving means for normally holding said lever out of said intermediate position; a locking member pivotally mounted at the other side of said bedplate; a second spring connected to said locking member; a stop pin for limiting the movement of said locking member by said second spring whereby said locking member is normally held in a position underlying said lever; a trip GEORGE V7. MCKINSTRY. 

